Generally, a water-cooling type engine of a vehicle includes a cooling system provided with a radiator and a flow control valve. The radiator is located in an engine coolant circuit for cooling the coolant. The flow control valve regulates the flow of the coolant that passes through the radiator. The flow control valve is controlled to change the coolant flow in the radiator (hereafter, “the radiator flow”). This adjusts the temperature of the coolant, which cools the engine.
The flow control valve is fully closed to minimize the radiator flow when the coolant temperature is relatively low. In contrast, when the coolant temperature is relatively high, the flow control valve is fully opened to maximize the radiator flow. Otherwise, a feedback control procedure is performed to vary the opening size of the flow control valve (the radiator flow) depending on the coolant temperature, such that the coolant temperature seeks a predetermined target.
To cool the coolant within the radiator, a cooling fan is mounted in close proximity to the radiator to providing cooling airflow to the radiator. Preferably, the cooling fan is coupled to the water pump.
However, many engine-cooling applications do not allow for conventional mounting of an engine-cooling fan on a water pump. For example, front wheel drive systems, or systems where the centerline of the water pump is not covered by the radiator, use electric motor driven systems or hydraulically driven fans to control the temperature of the coolant leaving the radiator. These systems are costly and inefficient.
Another potential issue related to cooling system performance is electrical power usage. As automotive manufacturers continue to introduce optional electrical equipment on automobiles, electrical demands within the vehicle correspondingly are increased. Further, customer demands for increased horsepower and towing capacity create additional demands on electrical systems. These extra demands place increased burdens on cooling systems to cool the engine compartment without significantly increasing electrical demand.
It is thus highly desirable to provide a way to cool an engine using an existing source of power that is economical and efficient.